11.In zinc blende structure coordination number of cation is

12.The existence of a substance in more than one solid modification is known as

13.When a cation and an anion are missing leaving behind a pair of voids, the defect is known as:

14.Edge length of a cube is 300 pm. Its body diagonal would be

15.In general, a crystal shows cleavage in a pattern which is specific for that type of crystal. This is because the atoms and molecules or ions in a crystal are